Abstract

There are very little attempts of DEM evaluation in such a disturbed or discontinuous surface (e.g., in tillage area). Present study aims to evaluate common interpolation methods (triangulation, nearest neighbor, natural neighbor, minimum curvature, multiquadratic radial basis function (MRBF), ordinary kriging, and inverse distance weight) in representing the detail topography of two different tillage types, namely bench terrace and furrow. Evaluation procedure was conducted through a stepwise analysis by using combination between the accuracy level (coefficient of determination (R2), mean error (ME) and standard deviation error (S)) and the shape similarity analysis. This study also shows the application of break-line function during the interpolation process in order to optimize some interpolation methods and the usage of drainage sink area as another step in evaluating DEM quality. To achieve the aim of this study, two field-size of dry-land agriculture (tegalan) were observed by using a set of total station Nikon DTM 322 with 3” angle accuracy. These plots, namely Tieng (1652 m²) and Buntu (673 m²), are situated in the upper part of Wonosobo District, Central Java Province, Indonesia. Tieng plot represents the bench terrace system embedded with stones on its terrace risers and showing relatively smooth ground surface. On the other side, Buntu plot shows the ridges and furrows system that lays perpendicularly to the contour lines. In terms of R², ME and S, there were slight differences in results between each method, except the multiquadratic radial basis function which was failed to generate terrace form in Tieng. The final result shows that triangulation is the best fit method followed by natural neighbour at representing the bench terraces in Tieng plot. In the case of furrow in Buntu plot, natural neighbour is the most accurate method. Despite its superiority at representing the bench terrace, triangulation has larger sink drainage area compared to natural neighbour. This study has confirmed the robustness of a stepwise analysis between quantitative and qualitative assessment techniques for DEM accuracy. A fine value of quantitative parameter does not necessarily mean that it will fairly possess a good spatial accuracy.

DOI number: 10.5027/jnrd.v3i0.13

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Abstract

The upward movement of water by capillary rise from shallow water-table to the root zone is an important incoming flux. For determining exact amount of irrigation requirement, estimation of capillary flux or upward flux is essential. Simulation model can provide a reliable estimate of upward flux under variable soil and climatic conditions. In this study, the performance of model UPFLOW to estimate upward flux was evaluated. Evaluation of model performance was performed with both graphical display and statistical criteria. In distribution of simulated capillary rise values against observed field data, maximum data points lie around the 1:1 line, which means that the model output is reliable and reasonable. The coefficient of determination between observed and simulated values was 0.806 (r = 0.93), which indicates a good inter-relation between observed and simulated values. The relative error, model efficiency, and index of agreement were found as 27.91%, 85.93% and 0.96, respectively. Considering the graphical display of observed and simulated upward flux and statistical indicators, it can be concluded that the overall performance of the UPFLOW model in simulating actual upward flux from a crop field under variable water-table condition is satisfactory. Thus, the model can be used to estimate capillary rise from shallow water-table for proper estimation of irrigation requirement, which would save valuable water from over-irrigation.

DOI number: 10.5027/jnrd.v3i0.12

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Authors

Alexander Neaman: Área del Medio Ambiente, Facultad de Agronomía, Pontificia Universidad Católica de Valparaíso, Quillota, Chile

Andrés Marió: Departamento de Formación Pedagógica, Universidad Metropolitana de Ciencias de la Educación, Santiago, Chile

Photo credits to: Francisco Vio

DOI number: 10.5027/jnrd.v3i0.11

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Abstract

Soil is an important natural resource which when effectively managed, could increase the livelihoods of households in sedentary agricultural communities. Soil erosion is however an emerging challenge as a cause of environmental degradation and this paper sought to ascertain the nature of soil erosion on maize farms, the effects of soil erosion on maize crop farmers and the effectiveness of local control measures on output levels and the livelihoods of the farmers. A cross-section of the community was taken and participants were selected non-probabilistically by snow-balling for questionnaire administration and focus group discussions. The study revealed that the local farmers perceived soil erosion as the wearing away of the top soil and nutrients, under the influence of running water during rainy periods and the slope of the land. The major effects of soil erosion were found to be the loss of fertile soils, reduction in the cultivable land area, the reduction in the crop yield and a fall in the living standards of farmers’ households. The findings also indicated that some of the adaptive strategies to reduce the effects of soil erosion include shifting cultivation, ridging across slopes, planting on raised mounds and avoidance of deep ploughing. It was further revealed that farmers who successfully applied the traditional methods improved upon their output levels per land area and the standards of living of their families It was recommended that modern agricultural extension services were needed, not to replace, but to complement the local knowledge systems in order to ensure sustainability.

DOI number: 10.5027/jnrd.v3i0.10

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Abstract

Many regions of the world face the challenge to ensure high yield with limited water supply. This calls for utilization of available water in an efficient and sustainable manner. Quantitative models can assist in management decision and planning purposes. The FAO’s newly developed crop-water model, AquaCrop, which simulates yield in response to water, has been calibrated for winter wheat and subsequently used to simulate yield under different sowing dates, irrigation frequencies, and irrigation sequences using 10 years daily weather data. The simulation results suggest that “2 irrigation frequency” is the most water-efficient schedule for wheat under the prevailing climatic and soil conditions. The results also indicate decreasing yield trend under late sowing. The normal/recommended sequence of irrigation performed better than the seven-days shifting from the normal. The results will help to formulate irrigation management plan based on the resource availability (water, and land availability from previous crop).

DOI number: 10.5027/jnrd.v3i0.09

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Abstract

The study essentially aims to assess the public-private partnership (PPP) as a thriving strategy in natural resources maintenance that largely is dependent on stakeholders’ participation forest bio-diversity and green management. In an age of climate change and global warming, as a threat due to unavoidable consequences of human activities, natural resource management is now one of the prime concern around the developed and developing countries in terms of creating responsible attitude towards green maintenance. Governments have, by and large, agreed on sustainable employ and conservation of forests in several international forums during the last three decades. In fact, public sector has already proved its inefficiency and ineffective mode to protect natural resources due to lack of skills, human and material resources, and rampant corruption which have encouraged the government to introduce the strategy of PPP. The study was conducted at Lawachhara national park through a sample survey by employing stratified sampling as well as some other tools of data collection incorporating both quantitative and qualitative approaches. It is evident in the study that most of the respondents commonly believe PPP may change the existing ineffective and inefficient mode of natural resources management. Another important finding included that challenges are not possible to overcome unless the active participation of the stakeholders are possible to ensure.

DOI number: 10.5027/jnrd.v3i0.08

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Abstract

This research was conducted at the southern coastal area of central Java Island, Indonesia. It is aimed to identify several coastal vegetation characteristics for development of guideline for planning and design of tsunami mitigation. Survey method was applied to observe common coastal vegetation in the research area. Data collected from the survey consisted of vegetation parameters and coastal morphology. All selected vegetations were analyzed for their allometry relation of each species, maximum density, correlation between breaking moment and trunk diameter of each tree species, and correlation between trunk diameter and spacing between trees for each species. For coastal morphology, it was focused on topography and elevation from sea level.
The results show that trees with the hard wood will be stronger to hold the pull moment on the main trunk. Younger trees with smaller diameter tend to be more flexible, thus they will unbreakable during the test. The other trees which have flexible trunk such as Terminalia catappa and Anacardium occidentale were often pulled out their roots than broken on their trunks. To obtain more extensive characteristic, it is necessary to carry out advanced measurements, especially on the older trees which have more than 10 cm diameter.
Coastal areas consist of mud and sand materials tend to have a high tsunami risk, although mitigation treatments were different for both types. At the muddy area, the recommended vegetation are Avicennia marina and Rhizophora mucronata, meanwhile Casuarina equisetifolia and Anacardium occidentale, due to their high flexibility, will be more suitable on the sandy coast. Both types should be planted parallel to the shoreline. Casuarina is planted in the frontline followed by Anacardium behind it.

DOI number: 10.5027/jnrd.v3i0.07

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Abstract

This study aims at investigating the nexus between natural resource endowment and economic growth using a sample of West African countries. The study adopted a Barrow-type growth model to analyse the impact of natural resource wealth on economic growth. A dynamic panel estimation technique was employed using relevant data from West African Countries. The results from the panel regressions indicate that natural resource endowments have very minimal impact in terms of promoting economic growth in West Africa, more so in resource rich countries. In terms of relative effects, the results indicate that a 10% increase in natural resource export reduces growth in income per capita by approximately 0.4%. Part of the factors explaining this finding amongst others; include high corruption in the public sector as well as the frequency of civil conflicts in resource rich economies of West Africa. For the natural resources of the region to fully benefit its citizens, these countries require , urgently, to improve management of natural resource export revenues and to apply effective policy measures to eradicate/ mitigate incidences of rampant corruption in the public sector.

DOI number: 10.5027/jnrd.v3i0.06

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Abstract

In Vu Gia-Thu Bon river basin, Vietnam, drought during the dry season affected negatively on rice production. High and uneven rainfall distribution cause flooding in the basin during wet season and cause severe agricultural drought during dry season.

This study aimed to point out a higher water productive and economically efficient rice production method to adapt water scarcity in the region. Based on available secondary data, water productivity is calculated for different water saving rice production methods, according to Pereira, et al, (2012)’s irrigation water productivity and total productivity equations. The profit of technological change is calculated by partial budget analysis of rice production in that area and a sensitivity analysis supports to point out which input factor is sensitive to farmer’s benefit. Farmer’s psychological and social beliefs are used to create fuzzy logic based decision making model. Although water productivities (ranging 0.441 kg/m3/ha   to   0.504 kg/m3/ha) are ranked as the second after System of Rice Intensification, we demonstrated that Alternate Wetting and Drying method is a recommendable method to the farmer after considering economic profitability and technical simplicity. The System of Rice Intensification method also could be a suitable method to adopt because this method is the highest water productive method (Water Productivities are ranging from 0.77 kg/m3/ha   to 1.02 kg/m3/ha) coupled with highest yield of rice, subject to certain ecosystem services and payment policies should be developed to subsidize the reduced benefit resulting from this method.

DOI number: 10.5027/jnrd.v3i0.05

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Abstract

Within the last decades, Kathmandu Valley in Nepal has been characterized by rapid population growth and related urbanization processes, leading to environmental degradation, pollution and supply bottlenecks in the metropolitan area. Effects of climate change are now putting additional stress on the urban system. In our research in Kathmandu, we carried out community and household surveys to analyze community perception on climate change and climate-related disaster preparedness. For this purpose, three categories of communities, 12 in all, were surveyed and interviewed: Squatter settlements, agricultural villages, and traditional villages. All settlements are located close to main rivers and therefore especially exposed to floods and droughts, and in slope position also to landslides. As a main result, we can conclude that people are generally aware of climate change and its potential consequences, such as climate change-related disasters. However, in their daily lives, climate change does not play a significant role and most communities have not taken any adaptation measures so far.

DOI number: 10.5027/jnrd.v3i0.04

 

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